1. Field of the Invention
The present invention relates to an information recording medium (or data structure), an information recording/playback method, and an information recording/playback apparatus, which are suited to record/play back a digital stream signal used in digital TV broadcast or the like.
2. Description of the Related Art
In recent years, TV broadcast has entered the era of digital broadcasts having Hi-Vision programs (programs of high-definition AV information) as principal broadcast contents. The current digital broadcast (and forthcoming terrestrial digital broadcast) adopts an MPEG transport stream (to be abbreviated as MPEG-TS as needed hereinafter). In the field of digital broadcast using moving pictures, MPEG-TS will be used as a standard format in the future. At the start of such digital TV broadcast, market needs for a streamer that can directly record digital TV broadcast contents are increasing.
As an example of a streamer that utilizes an optical disc such as a DVD-RAM or the like, “recording/playback apparatus” (Jpn. Pat. Appln. KOKAI Publication No. 2002-84479) is known.
Different digital broadcast schemes are adopted in respective countries: for example, DVB (Digital Video Broadcasting) in Europe; ATSC (Advanced Television Systems Committee) in U.S.A.; and ARIB (Association of Radio Industries and Businesses) in Japan.
In DVB, the video format is MPEG2, the resolutions are 1152*1440i, 1080*1920(i, p), 1035*1920, 720*1280, (576, 480)*(720, 544, 480, 352), and (288, 240)*352, the frame frequencies are 30 Hz and 25 Hz, the audio format includes MPEG-1 audio and MPEG-2 Audio, and the sampling frequencies are 32 kHz, 44.1 kHz, and 48 kHz.
In ATSC, the video format is MPEG2, the resolutions are 1080*1920(i, p), 720*1280p, 480*704(i, p), and 480*640(i, p), the frame frequencies are 23.976 Hz, 24 Hz, 29.97 Hz, 30 Hz, 59.94 Hz, and 60 Hz, the audio format includes MPEG1 Audio Layer 1 & 2 (DirecTV) and AC3 Layer 1 & 2 (Primstar), and the sampling frequencies are 48 kHz, 44.1 kHz, and 32 kHz.
In ARIB, the video format is MPEG2, the resolutions are 1080i, 720p, 480i, and 480p, the frame rates are 29.97 Hz and 59.94 Hz, the audio format includes AAC (MPEG-2 Advanced Audio Coding), and the sampling frequencies are 48 kHz, 44.1 kHz, 32 kHz, 24 kHz, 22.05 kHz, and 16 kHz.
In this manner, streams to be decoded by the apparatus side have many different variations for respective areas, and if all these variations are supported, the arrangement of a recording/playback apparatus (e.g., a DVD recorder) becomes considerably heavy (or completed). As a result, the apparatus cost increases.